Latch mechanism



Feb. 23, 1960 K. H. GRANZOW LATCH MECHANISM Filed April 4, 195a INVENTOR. @2119. Gimzau/ fl$m /f United States Patent LATCH MECHANISM Kurt H. 'Granzow, Sterling, Ill., assignor to Lawrence Brothers, Inc., Sterling, Ill., a corporation of llhnois Application April 4, 1958, Serial No. 726,402

2 Claims. 01. 292-113) This invention relates to a latch mechanism and more particularly to an improved latch mechanism for use in connection with sliding doors.

Sliding doors have become increasingly more popular for communicating rooms in modern buildings. Such doors conserve room space and present attractive appearance. It is desirable that locks be provided for the sliding doors to assure privacy of the rooms so separated. Since the sliding doors are opened and closed by pulling the doors in a desired direction, it is advantageous to provide a lock which releases by the application of a force to a lock handle in the direction in which it is desired to move the door. Conversely, it is desirable to provide a lock which locks by an application of force in the opposite direction to latch the door and close it at the same time.

One of the objects of the present invention is to provide a latch mechanism which is unlatched by moving a portion of an actuating mechanism in the same direction as the door is moved for opening.

Another object of the instant invention is to provide a protruding latch member that is always in condition for automatically engaging a striker plate.

A further object of the herein disclosed invention is to provide a latch mechanism which may be locked either prior to closing the door, or after closing the door.

A still further object of the present invention is to provide a latch mechanism which has relatively few parts and may be economically produced.

Another object of the instant invention is to provide a latch mechanism which may be easily installed by a carpenter.

. Other objects and advantages of the herein disclosed invention will be apparent from the appended specification and the accompanying drawings, in which:

'Fig. 1 is a perspective view of an assembly embodying the present invention;

Fig. 2 is an enlarged side elevation with a portion broken away showing a latch mechanism embodying the instant invention;

Fig. 3 is a cross sectional view similar to Fig. 2 showing a latch pin in a partially extended position;

Fig. 4 is a cross sectional view showing the latch pin engaging a striker plate;

Fig. 5 is a cross sectional view taken on line 5-5 of Fig. 3; and

Fig. 6 is an exploded perspective view of some of the parts of the latch mechanism.

Referring now more particularly to the drawings, there is shown in Fig. 1 a sliding door assembly including a sliding door 10, door jambs 12 and 14 associated therewith and a latch mechanism, generally indicated by numeral 16, for holding the door in. closedposition.

The invention herein disclosed is particularly adapted for use in connection with sliding doors that separate two rooms, as opposed to doors used for cupboards, closets, or the like, although the invention may have use with the latter. It is desirable that such doors be provided with a lock so that the privacy of the persons in either room 2,926,037 Patented Feb. 23, 1960 may be assured. The construction of the door and of the door jambs or casing in which the door slides may be any standard type of construction.

A striker plate 18 is mounted on jamb 12. As may be seen in Fig. 4, the jamb 12 has a recess cut therein and a domed recess plate 20 is positioned in said recess. The recess plate 20 and the striker plate 18 are fixed to the jamb 12 by a pair of screws 22 which extend through holes in the striker plate and recess plate. The striker plate 18 contains a latch aperture 24 in the central portion thereof for receiving a portion of the latch mechanism 16.

The latch mechanism 16, which is mounted in door 10, is engageable with the striker plate to lock the door to the door jamb 12. Said latch mechanism includes a casing assembly 26 for housing parts of said mechanism. A relatively long latch pin 30, which is movable in said casing assembly, is engageable with the striker plate to lock the mechanism to said plate. A fulcrum pin 28 mounted in the casing assembly provides a fulcrum means for said latch pin, and actuating means, generally indicated by numeral 32, is connected to one end of the latch pin 30. A spring 34 positioned between the latch pin 30 and the upper portion of the casing assembly 26 constantly urges the latch pin downwardly.

The aforementioned casing assembly 26 includes a baseplate 36, which is registerable with the striker plate 18, and said base plate has a latch aperture 38 in the central portion thereof. The casing assembly also includes a recess dome 40, which has a flange 42 integral with its outer edge and a latch tube 44 opening into the central portion of the dome 40. Said casing assembly is mounted within a recess 46 in door 10, which recess has a cylindrical opening 48 communicating therewith. The casing assembly 26, which provides a casing means, is fixed in door 10 by a pair of screws 50 which extend through the baseplate 36 and the flange 42 into the door 10 as may be seen in Figs. 2, 3 and 4.

The latch pin 30 has a hook or engaging means 52 integral with one end for releasably locking the latch mechanism to the striker plate. Said hook has a surface 54 for engaging the outer surface of the striker plate 18 and camming the pin 30 upward so that the hook 52 is in position to be inserted through the opening 24 of the striker plate as pin 30 is moved toward the door jamb. When the hook 52 is positioned behind the striker plate, the spring 34 forces the pin 30 downward so that a locking surface 56 engages the inner surface of the striker plate.

The end of latch pin 30 opposite the book has an enlarged portion 57 which contains an actuating pin receiving aperture 58. The latch pin includes a body portion 60, which body portion joins the enlarged portion 57 and the hook 52. The body portion 60 has a pin recess 62 formed therein for receiving the fulcrum pin 28, and proximate the pin recess 62, the body portion 60 has a cam surface 64 which blends into the pin recess 62.

The actuating means 32, which is in operative engagement with the latch pin 30, includes an actuating pin 66 having a diameter less than the diameter of the actuating pin receiving aperture 58. The pin 66 is fixed at one end to one end of an actuating arm 68 and a second actuating arm 70 is pivotally attached to the other end of the pin 66. I A handle 72 is fixed to the other end of actuating arm 68 and a screw 74 is fixed to the other end of arm 70.

The actuating means 32 is mounted within a circular receiver 76 in door 10, which receiver 76 opens into cylindrical hole 48. The actuating means 32 is pivotally supported within the receiver 76 by a pair of pull plates 77. The handle 72 is pivotally mounted in one of the pull plates and the screw 74 is pivotally mounted in the other of said pull plates as may be seen in Fig. 6. Said pull plates are held in the door by a plurality of wood screws 78, which extend through holes in the pull plates.

As may be seen in Fig. 6, the spring 34 is generally V-shaped. A hook 80 is integral with one of the arms of the spring. When the spring is placed in its operative position between the latch pin 30 and an interior surface of the tube 44, the hook 80 is positioned in a hook opening in dome 40 to hold the spring in position.

The door 10 is prepared to receive the latch mechanism 16 by having a circular receiving hole 76 drilled therethrough. The recess 46 is cut in the door and then the circular opening 48 is cut out between the recess 46 and the receiver 76. The casing assembly 26, with the fulcrum pin fixed therein, and the latch pin and spring positioned within the assembly, is positioned within the recess 46 and opening 48. The screws 50 are then screwed into place to fix the assembly within the door. The pull plate 77 with the handle 72 pivotally mounted therein is then positioned over one side of the receiver 76 and the actuating pin 66 is positioned within the opening 58. The plate 77 is then fixed to the door by means of a pair of screws 78. The second plate 77 with the screw head 74 pivotally mounted therein is then placed over the other side of the receiver 76 and the arm 70 is positioned in engagement with actuating pin 66, and second plate 77 is then fixed to the door 10 by a second pair of screws 78.

As may be seen in Fig. 2, the latch pin 30 may be retracted so that the hook 52 is positioned within the casing assembly 26. The latch pin 30 is projected outward from the casing assembly by moving handle 72 to the left. The pivoting of the handle pivots arm 68, which in turn moves the latch pin 30 to the left, so that the hook 52 extends beyond the casing assembly in a locking position as may be seen in Fig. 4.

Door 10 is locked by moving the door toward jamb 12 with the latch pin 30 in a locking position. As the door comes in proximity to the jarnb 12, the hook 52 engages the striker plate 18 and the engaging surface 54 cams the latch pin 30 upward as the door progressively moves closer to jamb 12. Hook 52 enters the aperture 24 and spring 34, which applies a continual downward force, forces the latch pin downward so that locking surface 56 engages the inner surface of the striker plate. Thus, the door 10 is releasably locked to the door jamb 12 by the engagement of the latch pin with the striker plate as shown in Fig. 4.

The door is unlocked by pivoting the handle 72 to the right, which is the same direction that the door is moved to an open position. As handle 72 is pivoted to the right,

actuating arm 68 and actuating pin 66 are also pivoted to the right. The pivotal movement of the pin 66 pivots latch pin 30 about the fulcrum pin 28 so that the hook 52 rises upward and the pin moves to the right to engage cam 64. It may be seen that the locking surface 56 is not parallel to the striker plate so that the rearward motion may be accommodated. Furthermore, the actuating pin has a diameter less than the diameter of pin aperture 58 so that there may be a slight adjustment of the pin within the aperture as the pin 66 applies a direct retractive force to the latch pin. When the latch pin reaches the position shown in Fig. 3, the pin is partially retracted to the casing assembly and the door may be opened. Further movement of the handle retracts the pin wholly within the casing assembly as shown in Fig. 2.

The handle may be turned slightly to unlock the door and then released so that the pin is retained in an extended position without turning it to its wholly retracted position as shown in Fig. 2. Thus, an operator may selectively position the latch mechanism in a locking attitude or in an unlocking attitude.

When the door is pulled to the left to close the door, the handle may be simultaneously pivoted to the left to extend the latch pin to a locking position in the manner described above. It may be seen that the locking and unlocking of the door is accomplished with the same movement which closes and opens the door respectively.

While a specific embodiment of the herein disclosed invention has been shown it is evident that modifications and changes may be made without departing from the spirit and scope of the herein disclosed invention as defined in the appended claims.

The invention is claimed as follows:

1. A latch mechanism for sliding doors, and comprising casing means to be fixed to the door and having a front opening, said casing means having a portion thereof defining a passageway open at both ends thereof, an elongated and unitary latch pin having hook means at the outer end thereof and a shank passing freely through said passageway with the inner end of said shank projecting inwardly of the inner end of the passageway in all positions thereof, said hook means adapted to be projected outwardly through the front opening of said casing means for selectively engaging a strike plate means, the inner end of the shank of said latch pin having a transverse aperture therein, fulcrum means positioned below the latch pin and fixed to said casing means, a latch actuating member to be mounted on the door for rotation about a first pivotal axis disposed above the longitudinal axis of the shank of said latch pin and rearwardly of said fulcrum means, a pivot means extending through said transverse aperture and engaging said actuating member to connect the latch pin and actuating member and define a second pivotal axis disposed parallel to and offset below the first pivotal axis, the second pivotal axis being located forwardly of a vertical plane containing the first pivotal axis when the latch pin is in extended position and the second pivotal axis being disposed below the first pivotal axis and rearwardly of the said vertical plane when the latch pin is in retracted position, the inner open end of the passageway in said casing means terminating short of the forward position of the second pivotal axis when the latch pin is in extended position whereby to eliminate the possibility of interference with the actuating member, the lower surface of the shank of said latch pin including a cam surface along the bottom thereof engageable with said fulcrum means, said cam surface cooperating with the fulcrum means during shifting of the latch pin by the actuating member to elevate the latch pin in an intermediate position thereof and to permit the latch pin to descend to lower positions at the extreme extended and retracted positions thereof, and spring means between the casing means and latch pin maintaining the upper surface of the shank of the latch pin out of contact with the casing means in all positions thereof and biasing the latch pin against the fulcrum means.

2. A latch mechanism as claimed in claim 1, wherein the spring means comprises a leaf spring of generally Z-shape configuration having one end attached to the casing means and the opposite end in relative sliding engagement with the upper surface of the shank of the latch pin.

References Cited in the file of this patent UNITED STATES PATENTS 

